A photograph of slain Filipino opposition leader Benigno S. Aquino Jr. has hung like an icon at every political rally held in Los Angeles in recent months to boost the election campaign of his widow, Corazon Aquino, against incumbent President Ferdinand E. Marcos.

But when Aquino supporters called a Los Angeles press conference Tuesday to urge President Reagan to denounce reported violence and fraud in the Feb. 7 presidential election--whose outcome still is in doubt--a new picture had joined that of the opposition presidential candidate's dead husband.

"One of our former residents and opposition leaders, who went back to the Philippines two years ago to help restore peace and democracy . . . was brutally assassinated in broad daylight (Tuesday)," said Eric Furbeyre, a spokesman for supporters of the Corazon Aquino campaign.

'Sacrificed Everything'

"Evelio Javier sacrificed everything," Furbeyre said, his face shaking with grief and tears welling in his eyes. "He has left a widow and two young boys here in Los Angeles. He went back knowing he would risk his life. . . . He was my business partner and friend."

Javier, governor of Antique Province in the Philippines from 1972 to 1980, spent the early 1980s in the United States, earning a master's degree from Harvard University and then settling in Hollywood. His wife, Precious, and two sons, Gideon and David, stayed behind "for reasons of safety" when he returned to his homeland to join the opposition struggle, Furbeyre said Tuesday. "He himself knew, when he left, that there was risk."

Speakers at the press conference--held immediately after Reagan's televised press conference from Washington--criticized the President for failing to issue a stronger denunciation of fraud and violence in the election, but expressed relief that he stopped short of stating that Marcos had won.

"We cannot understand why he (Reagan) cannot come up with a strong statement on this election rigging . . . ," said Danny Lamila, a director of the U.S.-based Ninoy Aquino Movement, at whose office the press conference was held. "Is the interest of the American people only in the (U.S. military) bases in the Philippines, or for the democratic process as a whole to flourish in that nation?"

Questions U.S. Policy

Citing Javier's death and the reported killings of more than 100 Filipinos in election-related violence, Furbeyre asked: "Are these lives of the Filipinos of less value than so-called American real estate or the U.S. bases?"

Word of Javier's death reached many opposition leaders in Los Angeles through a phone call from former Philippine congressman Raul Daza, a U.S. resident presently assisting Aquino in the Philippines, to his wife, Tess Daza, at their Pasadena home.

"He called me last night and he told me that news--'Tell the group that they just assassinated him,' " Tess Daza said. "Aquino won in that place (where Javier had been working for her campaign). Marcos wants to eliminate the people who make Aquino win. I am afraid for my husband too. I said, 'When are you coming home?' He said, 'In one week.' I said, 'If you do not come in one week, I am coming to pick you up.' I am afraid for his life, after what they have done to Javier."